AI 中文总结
NOvA实验发现标准Geant4模拟中子候选事件过剩，归因于高能中子产生的次级光子过多，采用数据驱动的中子-碳模型\tenate后改善一致性，并提示GENIE可能过度产生初级中子。
AI 中文摘要
中子对能量重建至关重要的中微子实验可能构成重大挑战。由于中子能够完全逃逸探测，且其动能与最终能量沉积之间的相关性较弱，因此难以完全计入中微子相互作用中产生的中子。这进而导致在评估与中子相关的系统不确定性时产生显著的模型依赖性。NOvA实验是一项长基线中微子振荡实验，其近探测器收集了高统计量的反中微子数据样本。我们报告了使用标准Geant4物理列表时，模拟的低能量沉积中子候选事件相对于数据的过剩。该模拟过剩可追溯至动能大于20 MeV的中子与物质相互作用产生的次级光子过多。通过将数据驱动的中子-碳相互作用模型\tenate应用于20 MeV至约100 MeV之间的中子，获得了与数据更好的吻合。使用\tenate后，残余的过度模拟在量热中子能谱上更加均匀，这表明GENIE中微子相互作用生成器可能过度产生了初级中子。这些结果促使采用\tenate补充的Geant4模拟作为未来NOvA模拟生产中的标称模拟。
英文摘要
Neutrons can present a significant challenge for neutrino experiments in which energy reconstruction is critical. With the ability to escape detection completely and with a weak correlation between their kinetic energy and any eventual energy deposition, it is difficult to fully account for neutrons produced in neutrino interactions. This in turn leads to significant model dependence when evaluating neutron-related systematic uncertainties. The NOvA experiment is a long-baseline neutrino oscillation experiment with a high-statistics sample of antineutrino data collected by its near detector. We report an excess relative to data of simulated neutron candidates with low energy depositions when using standard Geant4 physics lists. The simulation excess is traced to an overabundance of secondary photons produced from interactions of neutrons with kinetic energy greater than \SI{20}{\mega\eV}. Improved agreement with data is obtained by applying the data-driven neutron-on-carbon \menate model for neutrons between \SI{20}{\mega\eV} and ${\sim}$\SI{100}{\mega\eV}. With \menate, the residual oversimulation is more uniform across the calorimetric neutron energy spectrum, suggesting possible overproduction of primary neutrons by the GENIE neutrino interaction generator. These results motivate the adoption of \menate-supplemented Geant4 simulation as the nominal simulation in the production of future \nova simulation.
Comments19 pages, 10 figures
